How long do you want to live?

[Jeunemaitre]

We have no cure for Alzheimer's... how would that be addressed?

That depends on whether your in favor of allowing stem cell research. Also of note, several drug manufacturers are engaging in research in "Mild Cognitive Impairment" which some people feel is a "pre-Alzheimer's" state. One of the difficulties in such research is identifying non-demented participants who show signs of MCI. Once you get to the point of dementia, it's difficult to isolate deteriorating cognitive function from the effects of dementia through objective, or even subjective rating scales.

The thing to remember is that not that long ago, a diagnosis of any form of cancer was essentially a "You have x months to live" situation. Now, there are many forms of cancer that are coming under control, and others that are showing positive signs of a "cure" coming soon. Though we are fragile beings, we've amassed enough knowledge to be sufficiently capable of solving most biologic, or biochemical problems, given sufficient time and attention.

Of greater consequence (to me anyway) is the ability to adapt to a changing environment. We've always been inclined to adapt to changes in environment through the use of increasingly complex technology. I'm not convinced that we are flexible enough to adapt to changes that would take place in our environment over the course of en extended life-span.